$ git pull
Enter passphrase for key '/Users/sugyan/.ssh/id_rsa':
You asked me to pull without telling me which branch you
want to merge with, and 'branch.master.merge' in
your configuration file does not tell me either. Please
name which branch you want to merge on the command line and
try again (e.g. 'git pull <repository> <refspec>').
See git-pull(1) for details on the refspec.
If you often merge with the same branch, you may want to
configure the following variables in your configuration
file:
branch.master.remote = <nickname>
branch.master.merge = <remote-ref>
remote.<nickname>.url = <url>
remote.<nickname>.fetch = <refspec>
See git-config(1) for details.